JPH04109928A - Thermometer - Google Patents

Abstract

PURPOSE:To reduce the cost and make the whole device compact by calculating a temperature of a subject body based on an electric signal output from an infrared senser in a measuring preparation condition, an electric signal output in a measuring condition, and an electric signal output from a temperature- sensitive senser in a measuring condition. CONSTITUTION:When a probe 8 is inserted into an ear hole, with a start switch 5 pushed, computation is started by a computation processing means mounted in a circuit board, and a body temperature is displayed in an LCD display part 3. The computation processing means comprises amplifiers 41, 42 for amplifying electric signal outputs from an infrared senser 14 and a temperature- sensitive senser 11, an A/D converter 43 for converting an amplified electric signal output into a digital signal, a memory 45 for memorizing data, and a central processing unit (CPU) 44 actuated by instructions by the start switch 5 or a reference switch 7 for receiving a digital signal from the A/D converter 43 to let it memorized in the memory 45, reading data and performing various computation to light a measurement permitted display LED 6, or displaying a result of measurement in a display device 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermometer, and more particularly to a radiation thermometer that detects infrared rays emitted from an object to be measured, such as an eardrum, and measures the temperature accordingly.

Conventional technology In recent years, this type of radiation thermometer has been developed, proposed, and investigated as a device suitable for measuring the body temperature of patients in hospitals, etc., because it can significantly shorten the time required for temperature measurement. There is. The conventionally known technology is JP-A-61
There were those disclosed in JP-A-117422 and JP-A-2-28524. In all of the thermometers disclosed in these publications, a metal tube as a waveguide is attached to the tip of an infrared sensor such as a thermopile, the whole is covered with a heat insulating material, and such a blow 7 is inserted into the external ear canal. By inserting the device, infrared rays from the eardrum are guided to the infrared sensor to measure body temperature. In order to ensure accuracy as a thermometer,
In the method disclosed in Publication No. 117422, the entire measurement system is kept at a constant temperature of body temperature level (36
, 5°C) to eliminate various error factors. Further, in the method disclosed in Japanese Patent Application Laid-Open No. 2-28524, accuracy is ensured by using various correction calculating means 5).

Problems to be Solved by the Invention However, the conventional thermometers described above have the following problems.

First, the technique disclosed in JP-A-61-117422 requires (1) stabilization time for preheating;

(2) A highly accurate heating control device is required, which complicates the circuit and increases costs.

(3) A large amount of electric power is required to drive the heating control device, and therefore the size is large.

There was a problem.

Next, the technique disclosed in Japanese Unexamined Patent Publication No. 2-28524 does not use a heating device for preheating, so the above-mentioned problem is solved. However, if the heat balance of the entire system is not maintained, a temperature sensor is installed in the metal tube at the end of the infrared sensor, and the measured value is used to make corrections and calculate body temperature data. 1) Unbalanced heat: Well, there is a temperature gradient in the metal tube, and if you measure the temperature at the minus point and use the result as the metal tube temperature, a new error will occur.

(2) To avoid such errors, install another temperature sensor near the infrared sensor and calculate the temperature difference between the two.
A separate limit temperature is set and measurement is permitted. However, the circuits for these are complicated, increasing costs, and the conditions under which measurements can be made must become narrower.

There was a problem.

The object of the present invention is to provide a thermometer that can solve the problems of the prior art.

Means for Solving the Problems A thermometer according to the present invention includes an infrared sensor that receives infrared energy and outputs an electric signal corresponding to the infrared energy, a reference body that emits reference infrared energy, and a temperature sensor that detects the temperature of the reference body. a temperature sensor that outputs an electrical signal corresponding to the temperature; the infrared sensor receives reference infrared energy from the reference object in a measurement preparation state; and the infrared sensor receives infrared energy from the object to be measured in a measurement state; holding means for holding the infrared sensor and the reference body so as to receive the infrared sensor; and an electrical signal output from the infrared sensor in the measurement preparation state;
It is characterized by comprising a calculation means for calculating the temperature of the object to be measured based on the electrical signal output of the infrared sensor and the electrical signal output of the temperature sensor in the measurement state.

Embodiments Next, the present invention will be described in more detail with reference to embodiments of the present invention based on the accompanying drawings.

1 is a schematic perspective view showing a thermometer as an embodiment of the present invention, FIG. 2 is a schematic side view of the thermometer shown in FIG. 1, and FIG. 3 is a schematic side view of the thermometer shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view of the probe portion. As shown in FIGS. 1 and 2, the thermometer of this embodiment includes a main body 1 and a probe unit 2 placed on the main body 1. The main body 1 has a built-in circuit board (not shown) for performing arithmetic processing, etc. as described later, and also has a power supply for energizing such circuit means. A switch 4 and a reference switch 7 are provided, and an LCD for displaying temperature measurement results is provided.
A display section 3 and a measurement permission display LED 6 are provided. Furthermore, a hole 9 is formed in the main body 1, and a reference body 10 is placed at the bottom of the hole 9 by means of a main hole. A temperature sensor 11 is attached to the reference body 10, and an electrical signal output from the temperature sensor 11 is connected to a circuit board via a wire 13. The reference body 10 is preferably formed of a material with high emissivity and good thermal conductivity, such as a metal coated with paint (without gloss), or with a black paint. Any device capable of detecting temperature may be used, for example, a temperature sensitive diode.

On the other hand, the probe unit 2 in this embodiment is formed separately from the main body 1, is provided with a start switch 5 for notifying the start of calculation, which will be described later, and has a probe 8 at its tip. Probe unit 2 like this
As clearly shown in FIG. 2, the probe unit 2 is set on the main body 1 with the probe 8 inserted into the hole 9 of the main body 1. When the reference body 10 is centered on the main body 1, the reference switch 7 provided on the top surface of the main body 1 is activated by the probe unit 2, indicating that the reference body 10 is in a state where it can be measured.

As shown in FIG. 3, the probe 8 of the probe unit 2 is provided with a fixing base 16,
An infrared sensor 4 such as a thermomobile and a metal tube 15 as a waveguide are provided. The infrared sensor 14 and metal tube 15 are surrounded by a heat insulating material 17. The electrical signal output from the infrared sensor 14 is sent to a circuit board in the main body 1 through a cord 18 and further through a cord 12 that connects the probe unit 2 and the main body 1. The tip of the probe 8 is covered with a cover 19 if necessary for hygiene reasons.

This cover 19 is for preventing direct contact between the probe and the ear canal, and is made of a material with low thermal conductivity. This cover 19 is provided so that the entire 1@ portion 23 is exposed inside.

On the other hand, the heat insulating material 17 of the probe 8 is provided with a pair of metal parts 22 that are spaced apart and exposed to the outer surface.

Conductive wires 24 connected to the circuit board of the main body 1 via the cords 12 are connected to these metal parts 22, respectively. As shown in FIG. 3, when the cover 19 is completely attached to the tip of the probe 8, the pair of metal parts 22 are electrically connected by the metal part 23, so the two conductive wires 24 are electrically connected to each other),
It is possible to notify the circuit board that the cover 19 is completely attached. Furthermore, a transparent filter 20 is provided at a portion of the tip of the probe 8 that corresponds to the metal tube 15, and a transparent filter 21 is provided at a position of the cover 19 that corresponds to the metal tube 15. Both transparent filters 20 and 21 are made of a material that transmits infrared rays.

When the probe 8 is set in the hole 9 of the main body 1, the reference body 10 faces the infrared sensor 14, and FIG. 3 schematically shows this state.

Next, we will explain in detail how to operate a thermometer with such a configuration. First, in the set state shown in FIGS. 1 and 2, turn on the power switch 4, turn on the measurement permission display LED 6, and then turn on the probe unit 2.
and insert the probe 8 into the ear canal. When the start switch 5 is pressed with the body firmly inserted, the arithmetic processing means mounted on the circuit board starts calculations as described later, and as a result, the body temperature is displayed on the LCD display section 3. The figure shows the probe 8 inserted into the ear canal, and in this figure, reference numeral 25 indicates the auricle, reference numeral 26 indicates the external ear canal, and reference numeral 27 indicates the ear canal.
Showing the eardrum. When measuring again, the probe unit 2 is re-inserted into the main body 1, and after the measurement permission display LED 6 lights up, the measurement is carried out in the same manner.

Next, the principle by which body temperature can be measured with such a thermometer of the present invention will be explained.

First, according to the Stefan-Boltzmann law, every object emits energy proportional to the fourth power of its absolute temperature.
radiates from the surface. Of course, probe 8 is in ear canal 2.
The output of the infrared sensor 14 in the state shown in FIG.
Here, P: Output Tk of the infrared sensor 14: Temperature of the eardrum T,: Temperature of the metal tube 15 To: Temperature of the infrared sensor 14 Ko: Constants of proportionality that do not depend on the physical constants of each part in the system a, b: System It is expressed as a proportionality constant that depends on the physical constants of each part within.

This will be explained in more detail with reference to the schematic diagram of FIG. That is, the infrared rays L6 emitted from the object 28 corresponding to the eardrum 27 reach the infrared sensor 14 either directly or after being reflected by the inner wall of the metal tube 15. This is (1)
This is the term (a'L=') in the formula. There is also infrared rays emitted from the metal tube 15 itself and reaching the infrared sensor 14. This is the term (bT,') in equation (1). The term (T o ') in the above formula (1) is the infrared sensor 1
4 represents the effect due to its own temperature, (a Tk'
The difference between b Tb' ) and (To') is the infrared sensor 1
It is proportional to the output of 4.

By the way, in order to obtain the eardrum temperature T using the above equation (1), the temperature Tb of the metal tube 15 and the temperature T of the infrared sensor 14 are
. Is required. When the metal tube 15 and the infrared sensor 14 are in a steady state, there is no change in temperature over time, and by attaching a temperature sensing element such as a diode, T,
,T, can be obtained. However, in cases where the steady state is disrupted due to body temperature or other factors such as repeated measurements, for example, even within the same metal tube 15,
Since the temperature differs depending on the location, it becomes extremely difficult to obtain the (bTb') term and (T.') term in the above equation (1). In practice, measurement is performed after waiting for a period of time (for example, about 10 minutes) to recover to a steady state.

Therefore, according to the present invention, measurement is first performed with the probe 8 set in the main body 1 (see FIGS. 1 and 2). The output of the infrared sensor 14 at this time is P' = Ko(a'Tr' l bTb" T
o”)・・・(2) where P′: Output Tr of the infrared sensor 14: Temperature T of the reference body 10,′: Temperature To′ of the metal tube 15: Temperature Ko of the infrared sensor 14: System Proportionality constants a' and b that do not depend on the physical constants of each part in the system: Expressed by proportionality constants that depend on the physical constants of each part in the system.This is the same as the equation (1) above.Immediately after this measurement The probe unit 2 is picked up and the eardrum temperature is measured in the state shown in FIG. and the temperature of the infrared sensor 14 is Tb
"Tb', To = To'. Therefore, at the beginning of the measurement, by subtracting the above equation (2) and the above equation (1), P' - P=, (a' Tr4 - aT*')
...(3) is found. In this equation (3), metal tube 1
It is clear that the effects of 5 and the infrared sensor 14 have been removed, and that it does not depend on the states of both. Furthermore, it becomes.

Since the temperature Tr of the reference body 10 can be detected by the diode 11, it is experimentally determined as K. , a,
If a' is determined in advance, it can be determined using the above equation (4).

According to the above operating principle, the metal tube 15 and the infrared sensor 14
However, even if the temperature is not in a steady state, this information is canceled out, so the eardrum temperature can be measured. Therefore, repeated measurements can be made without any time intervals.

Here, the actual change in pressure of the external sensor 14 is shown in the sixth section.
and FIG. FIG. 6: This is a case where the metal tube 15 and the infrared sensor 14 were in a steady state when measuring the reference body 10, and FIG. 7 is a case where they were not in a steady state. In both FIG. 6 and FIG. 7, reference numeral q
The line indicated by reference symbol r indicates the output change during measurement of the reference body 10, and the line indicated by the reference symbol r indicates the output change from the time when the probe unit 2 is removed from the main body 1 until the probe 8 is inserted into the ear canal. The line indicated by reference symbol S shows the output change after inserting the probe 8 into the ear canal. As shown by the line S, the output value temporarily decreases immediately after the probe 8 is inserted into the ear canal because the inside of the ear canal is cooled by the probe 8.

The time constant of the response of an infrared sensor is typically a few milliseconds,
And time constant of cooling and heating of hole and metal pipe: Well, Equation 1
00 milliJ seconds. Therefore, the peak value at the moment when the probe 8 is inserted into the ear canal is considered to be the output P of the infrared sensor 14 when measuring the eardrum. - The pressure value, which decreased over time, increases again as the temperature in the ear canal recovers and the temperature of the metal tube 15 increases.

The difference between Figure 6 and Figure 7 is that in Figure 6 '7), the line q
indicates that the pressure value of the infrared sensor takes a constant value, and ′J
), whereas in FIG. 7, the line q indicates that the output value of the infrared sensor changes. This is because the metal tube 15 and the infrared sensor 14 are not in a steady state, so that (bT,'') and (T
o”) changes over time. 6th
In the figure, the output P' of the infrared sensor 14 when measuring the reference body 10 may be the value of the constant portion indicated by the line q. In FIG. 7, P1' may be taken as P'. However, it is more accurate to take the estimated value P 21 at the time when the peak value F is output. Ideally, it would be good if the reference body 10 and the eardrum could be measured at the same time, but this is not possible, and after measuring the reference body 10 and before moving on to the eardrum measurement,
t, (1 to 2 seconds). Koma's line q for calculating the second estimated value P2'
It is sufficient that the extension line U is a tangent to the line q at the point ○ on the boundary between the lines q and r.

FIG. 8 is a professional diagram showing a circuit for arithmetic processing etc. configured on the circuit board in the main body 1. This circuit is as follows:
Mainly, an amplifier 41 for amplifying the electrical signal output from the infrared sensor 14, an amplifier 42 for amplifying the electrical signal output from the temperature sensor 11, and converting each amplified electrical signal output into a digital signal. A/D for
converter 43 and memory 4 for storing various data
5, and is activated by commands from the start switch 5 and the reference switch 7, receives digital signals from the A/D converter 43, stores them in the memory 45, reads data from the memory 45, and performs various calculations. Measurement permission is displayed and ED6 is lit, display device 3
It also includes a central processing unit (CPU) 44 for performing processing such as displaying measurement results.

Next, the procedure for calculating and displaying the temperature of the object to be measured by performing calculations based on the principles of the present invention as described above using the circuit configuration shown in FIG.
This will be explained with reference to Figure-1.

FIG. 9 shows an example of the contents of data stored in the memory 44, FIG. 10 is a flowchart showing the main routine, and FIG. 11 is a flowchart showing the timer interrupt routine.

After turning on the power switch 4, step 1 of the main routine
Initialize at step 00, then step 10
1 starts the interrupt timer. As a result, an interrupt is generated at fixed time intervals in the steps shown in the timer interrupt routine shown in FIG. Reference measurement (
In the measurement preparation state), reference data is stored in the memory 44 in order to obtain P'. Therefore, in step 200, it is checked whether the reference switch 7 is on, and if it is on, step 200 is performed.
1, increment the counter R, and step 202
At step 203, reference data is stored in the memory according to the counter value, and this is repeated until it is checked at step 203 that the counter R is equal to 3. As a result, as shown in FIG. 9, three pieces of reference data such as reference data (1), (2), and (3) are stored in the memory 44. Step 2
037: When the counter R reaches 3, the counter R is initialized and the R flag is set in step 204. , By repeating interrupts, the latest three reference data are constantly updated in the memory through these steps. When the R flag is checked in step 102 of the main routine, the measurement permission display LED 6 is turned on in step 103. At step 104, it is checked that the reference switch is not on.

Also, in step 205 of the timer interrupt routine,
After checking that P2' is not being calculated, the tympanic membrane measurement data is read into the memory at each interrupt. At this stage, it is necessary to obtain the peak value P, and for this purpose, in step 207, the data at the time of the current interrupt and the data at the time of the previous interrupt are compared, and (previous data) < (current data) If so, in step 208, the beak data stored in the memory shown in FIG. 9j is updated with the current data as the beak data. In this way, the peak data is updated, and finally, as proof that the true peak value P has become the peak data, in step 105, after checking whether the start switch 5 is turned on,
At step 10 of the main routine, it is confirmed that the ear canal is cooled. This is determined by checking in steps 209 and 210 of the timer interrupt routine in FIG. . In this way, after detecting ear canal cooling in step 106, in step 107, the time gradient of the reference is determined from the three reference data (1), (2), and (3) stored in the memory. P2' is calculated and the timer is stopped at step 108.

In this way, P' is determined in step 109, and step 1
In step 10, P was found, and P was obtained in this way,
From the value P' of P2' at that point, the eardrum temperature Tk is determined in step 111 using equation (4), and L
It is displayed on CD display B3. Then step 11
2, the measurement permission display LED is turned off, and step 113
Confirm that the reference switch is on and complete the series of temperature measurement operations.

12 and 13 show another embodiment of the invention, FIG. 12 being a side view and FIG. 13 being a rear view. The thermometer of this embodiment includes a probe unit 32, which includes a probe 8.
is provided.

The probe unit 32 is provided with a reference body 10 and a reference mask 31 having a diode 11 for detecting the temperature of the reference body 10. By pressing the lever 30, the reference mask 31 is rotated about the shaft 33 in the direction of the arrow, and the reference mask 31 is moved to a position where the reference body 10 faces the probe 8 (
12) and an open position away from the probe 8 (position shown by dotted lines in FIG. 12). If you stop pressing the lever 30, the reference mask 31 will automatically open.
The probe unit 32 returns to a position covering the probe 8.A power switch 4 is provided at the bottom end of the probe unit 32, a start switch 5 is provided at the back, and a start switch 5 is provided at the top of the back. is provided with an LCD display section 3 and a measurement permission display LED 6. The operating principle of the thermometer of this embodiment is exactly the same as that of the embodiment described above, and in the embodiment described above, the arithmetic processing section such as the circuit board provided on the main body 1 side is all located inside the probe unit 32. It is provided.

Next, to explain how to operate the thermometer according to the embodiment shown in FIGS. While pressing 30 with your fingers, insert the probe 8 into the ear canal. When the start switch 5 is pressed with the eardrum temperature firmly inserted, the eardrum temperature will be displayed on the display 3.
will be displayed. If you want to measure again, press lever 30 once.
After releasing the reference mask 31 and returning the reference mask 31 to its original position, the measurement permission display LED 6 lights up, and then measurement is performed in the same manner.

Effects of the Invention Since the thermometer of the present invention operates with the configuration described above, the following effects can be obtained.

(1) No heating device is required for preheating, so
The cost for this can be reduced, and since no space is required for this purpose, the overall size can be made smaller.

(2) By installing a reference body and a temperature sensor that detects its temperature, measurements can be made even if the thermal balance of the measuring device is disrupted, and therefore repeated measurements can be made quickly and accurately. Ru.

(3) Furthermore, in the case of the embodiments described with reference to FIGS. 12 and 13, in addition to these effects,
By integrating the reference body with the probe unit, it can be made more compact and has excellent portability. Furthermore, since it is not necessary to reset the probe unit to the main body each time a measurement is performed, it is possible to achieve excellent operability.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a thermometer as an embodiment of the present invention, FIG. 2 is a schematic side view of the thermometer shown in FIG. 1, and FIG.
The figure is an enlarged sectional view of the probe portion of the thermometer shown in Fig. 1, Fig. 4 is a schematic diagram showing the state in which the probe of the thermometer shown in Fig. 1 is inserted into the ear canal, and Fig. 5 is an operation of the thermometer of the present invention. FIGS. 6 and 7 are schematic diagrams for explaining the changes in the output of the infrared sensor, and FIG. 8 is a diagram showing how the output of the infrared sensor changes, and FIG. 9 is a diagram showing an example of the content of data stored in the memory of FIG. 8; FIG. 10 is a flowchart showing the main routine; FIG. 11 is a flowchart showing a timer interrupt routine, FIG. 12 is a side view of a thermometer according to another embodiment of the present invention, and FIG. 13 is a rear view of the thermometer shown in FIG. 12. 1... Body, 2... Probe unit, 3... LCD display, 4... Power switch, 5... Start switch, 6... Measurement permission display LED, 7... Reference switch, Death... Probe, 9... Hole, 0... Reference body, 1 ... Temperature sensor, 4 ... Infrared sensor, 5 ... Metal tube, 7 ... Heat insulation material, 9 ... Cover 5 ...Auricle, 6.. External auricular foramen, 7.. Tympanic membrane, 0.. Levert...Reference mask, 2..・Probe unit, 3...Glaze. Figure Figure Figure Time Figure Figure ○ Figure 12 Figure Figure Procedure Amendment 3, Person making the amendment Relationship to the case Applicant name Hise Electric Co., Ltd. 4, Agent 5, Date of amendment order Voluntary 6. Column 7 for detailed explanation of the invention in the specification to be amended, content of the amendment/1 memo of “memory 44” on page 18, line 1, page 19, and lines 2 and 10 of page 19. 45
＝ Corrected.

Claims (3)

[Claims] (1) An infrared sensor that receives infrared energy and outputs an electrical signal corresponding to it, a reference body that emits reference infrared energy, and detects the temperature of the reference body and outputs an electrical signal that corresponds to that temperature. a temperature-sensitive sensor, and the infrared sensor and a reference so that in a measurement preparation state, the infrared sensor receives reference infrared energy from the reference object, and in a measurement state, the infrared sensor receives infrared energy from the object to be measured. Based on a holding means for holding the body, an electrical signal output from the infrared sensor in the measurement preparation state, an electrical signal output from the infrared sensor in the measurement state, and an electrical signal output from the temperature sensor a calculating means for calculating the temperature of the object to be measured. (2) The holding means includes a probe unit and a main body on which the probe unit is placed, the infrared sensor is held in the probe portion of the probe unit, and the reference body is The thermometer according to claim 1, wherein the infrared sensor is held in a main body, and the infrared sensor faces the reference body when the probe unit is placed on the main body. (3) The holding means includes a probe unit and a reference mask attached to the probe unit, the infrared sensor is held in the probe portion of the probe unit, and the reference body is The probe unit is held by the reference mask, and the reference mask is movable between a position where the reference body faces the infrared sensor and a position where the infrared sensor is opened. The thermometer according to claim (1), which is attached to the thermometer.